This may be a stupid question but does one need to preload hydraulic lifters any differently with aluminum heads vs iron? (Using TA rollers) ...thermal expansion? ..just plain noisier? These are set per spec and I do notice after the engine has run at temp for some time the valvetrain is definitely noisier than with the old heads. (TA heads by the way) The only thing that has changed valvetrain-wise were the heads and we added custom length pushrods..all else is the same. I've had such a pleasantly quiet valvetrain for so long, it just gets my attention. Thanks!
Not with hydraulic, the heads do grow and with solid lifters you should factor that into your preload, but with hydro go 40 to 60 tho for quiet operation and 10 to 30 for a little looser setup, just be sure to try and get the adjuster cup level or one thread from it on the rockers.
Aluminum heads do grow some .008" when up to 200 degrees. A normal setting of 1/2 turn from the no slack point nets a preload of .030" with a fine tread stud which should be fine, but the other factors thrown into the mix are how much Aluminum rockers may grow and the same for push Rods. If a preload of .030" does not get you a noise free valvetrain then something is up!
Add .012 to your desired preload to account for cylinder head growth. Done many solid lifter motors, and lash checks on the dyno consistently show and increase of right around .012 with the engine at operating temp.
I just swapped out the Morel hydraulic roller lifters for Johnson roller lifters. The Morels were very noisy when the engine was hot. The Johnson lifters are MUCH quieter. The Morels were in at 3/4 of a turn on the roller rockers. The Johnsons at 1/2 a turn per JW's recommendation. The Johnson Lifters are shorter travel, so that plays into it as well. I have always found the aluminum heads to be somewhat noisy compared to the iron heads.
No, the Morels were the roller lifters that TA sold when they first marketed roller cams. I'm sure 1/2 a turn on the roller rockers would be fine. I know Jim used 3/4 of a turn on my Morel roller lifters, but they were noisy even at that preload. The Johnsons required less preload, so Jim told me to set them at 1/2 a turn. You will have to see. I think they will be noisy when hot. You can always turn them another 1/4 of a turn. Loose is better than too tight.
Not to hijack a thread here, just one quick question, if my solid was set to .022 cold, I honestly never checked them warm but the head had to grow some, since the AL heads grow about .012, should I start at .034, seems alot. I was thinking .028 to end up about the same I was running
It looks like when my guy did the final adjustment pre-dyno they were set just under 1/2 turn...on the loose side. Good news it's not an issue. Time to go break some more traffic laws.
That would be the opposite way because as the head expands Jim is saying that it grows .012" so cold you would need to subtract that much off of the lash not add it. Derek
Mike T told me .008 tighter for Solid flat tappet, if it was noisy at operating temp who would know Horsepower is loud